This invention relates to compressors and, in particular, to a discharge valve mechanism included in the compressors.
For example, an air conditioner often uses a so-called multicylinder compressor having a plurality of cylinder bores and a discharge valve mechanism corresponding to each of the cylinder bores. As the discharge valve mechanism, various types of mechanisms are proposed.
An example of the types is disclosed in Japanese Utility Model Application Publication No. H6-25576 (JP 6-25576 U) and comprises a valve plate having a plurality of discharge holes communicating with the cylinder bores, respectively. On an exit side of each of the discharge holes, a flexible plate-like discharge valve is overlapped with the valve plate.
The plate-like discharge valve has ends in a first direction parallel to the valve plate. One of the ends is fixed to the valve plate. Another of the ends is movable in a direction away from the valve plate with a bend of the plate-like discharge valve.
Furthermore, the discharge valve mechanism has a valve holder having a holding surface for limiting the bend of the plate-like discharge valve. The holding surface of the valve holder is inclined with respect to a second direction parallel to the valve plate and perpendicular to the first direction. With respect to the first direction, the holding surface of the valve holder is inclined and defines a curved surface. The curved surface has a substantially same radius of curvature at any part in the second direction.
The above-mentioned discharge valve mechanism is effective in suppressing noise of the compressor if the distance from the valve plate to the holding surface of the valve holder is reduced. In this case, however, the movable range of the plate-like discharge valve, i.e., the amount of lift of the valve is limited to be small. This may result in an increase of pressure loss at a high flow rate and an increase of internal pressure in each of the cylinder bores, leading to overcompression.
On the other hand, if the distance from the valve plate to the holding surface of the valve holder is increased, the overcompression is avoided but the effect of suppressing the noise of the compressor is insufficient.